Sand mulling and aerating machine



Nov. 8, 1938. w. H. NICHOLLS SAND MULLING AND AERATING, MACHINE FiledNov. 25, 1935 2 Sheets-Sheet l 1938. w. H. NICHOLLS 2,

SAND MULLING AND AERATING MACHINE Filed NOV. 25, 1955 2 Sheets-$heet 2Elma/rm Patented Nov. 8, 1%38 UNITED STATES PATENT OFFICE v 2,135,762SAND MULLING AND AERATING momma Application November 25, 1935, SerialNo. 51,540

2 Claims.

This invention is an improvement over the disclosure in my Patent No.1,636,384 granted July 19th, 1927.

The invention relates to foundry equipment and has particular referenceto means for preparing the sand used in forming molds.

The principal object of the invention, generally stated, is to provide ahighly eflicient, continuously operating apparatus for mulling the sand,finely dividing it and discharging it into the air in a difiused stateso as to effect aeration.

It is well known that machines of this general type embody rollers whichare driven over the bottom of the mulling basin for the purpose ofintermingling clay with the sand and for crushing or crumbling any lumpsof sand or sand and clay and working or what might be called kneadingthe sand mixture so that the entire mass thereof will be thoroughlybroken up and reduced to a condition of fineness appropriate for use informing molds. However, it has been found that the abrading action onthe bottom of the mulling basin results in serious wear, even to such anextent that destruction and consequent replacement is necessary in acomparatively short time.

It is with the above facts in view that I have devised the presentinvention which contemplates maintaining what might be called a cushionof sand which remains stationary while the rollers travel in theirorbits and which therefore does not produce any friction or abrasion onthe bottom of the basin, the life of the machine being consequentlygreatly prolonged.

A more specific object of the invention is to provide a mulling machineembodying rollers travelling in circular orbits, at least one of therollers having its periphery either circumferentially or transverselygrooved so that the roller will have a greatly increased crumbling ormulling action on the sand.

Another specific object of the invention, and one of tremendousimportance, is to provide a mulling machine in which the bottom of thebasin is formed with a series of concentric grooves within which thesand or mixture will pack and acquire a rock-like hardness, the sand,moreover, according to its natural tendency, projecting above the topsurface of the basin bottom and consequently defining ridges betweenwhich loose sand is entrapped and therefore held stationary, all thefriction and abrasive action therefore taking place upon the sand itselfinstead of on the bottom of the basin.

The invention further contemplates the provision in a machine of thischaracter of rreans for separating the sand finely after it has beenmulled and discharging it into the air in a diffused state so as toeffect aeration, these features being, however, disclosed in said priorpatent.

An additional object of the present invention is to provide a machine ofthe character set forth and for the purpose specified which will be notonly continuous and eflicient in its operation but which will be simpleand inexpensive to make, easy to use, positive in action, and a generalimprovement in the art.

To the attainment of the foregoing and other objects and advantages, theinvention preferably consists in the details of construction and thearrangement and combination of parts to be hereinafter more fullydescribed and claimed, and illustrated in the accompanying drawings inwhich:

Figure 1 is a plan view of the device with the shell in section,

Figure 2 is a central longitudinal sectional view through the machine,the view being taken on the line 2-2 of Figure l,

Figure 3 is a side elevation of a modified form of roller,

Figure 4 is an edge view thereof,

Figure 5 is a detail perspective view of sweeper means for dischargingthe sand from the mulling basin,

Figure 6 is a fragmentary enlarged detail section illustrating the sandpacked in the grooves and showing the action.

Referring more particularly to the drawings, the numeral I designatesthe baseof the machine above which is supported, by legs 2, a mullingbasin indicated as a whole by the numeral 3 and including a bottom 4preferably provided with an upstanding peripheral flange 5 locatedoutwardly of and constituting retaining means for a cylindrical shell 6which defines the side wall of the basin. Engaged upon the upper edge ofthis shell is a funnel member or hopper I having a central opening 8through which sand is fed into the basin.

The bottom 4 is formed or otherwise provided centrally with a bearing 9here represented as extending above and also below the bottom. Journaledthrough this hearing is a shaft l0 equipped at its lower end with arelatively large bevel gear II and having an enlarged portion l2 nearits upper end located above the bearing 9. This enlarged portion I2 isformed with diametrically opposite flattened areas l3 and is straddledby U-shaped yokes I 4, preferably lapped as shown in Figure l, and whichare pivotally mounted as by a pin or bolt I 5 so as to have limitedvertical swinging movement. These yokes carry shafts l6, upon one ofwhich is journaled a roller l1 and upon the other of which is Journaleda roller iii. The exact mounting for these rollers may be consideredmore or less immaterial but in the present instance they are representedas held in place by nuts I9 screwed onto the threaded ends of the shaftsl6. Fixed with respect to the shafts I 6 are collars 20 received withinrecesses 2| and formed with grooves 22 filled with appropriate packingfor the purpose of excluding the sand from the bearing surfaces withinthe rollers. The lapped relation of the yokes I4 is clearly shown inFigure 1 and the purpose is to offset them relatively so that the shaftsl6 will be out of diametric alinement so that the rollers shall have asweeping action, the eccentric mounting tending to cause the sandmixture to be gradually moved outwardly toward the discharge opening ofthe basin.

It is a very important feature of the present invention that one or evenboth of the rollers should be corrugated or formed with alternatingridges and grooves. In the present instance only the roller I8 isdisclosed as grooved, the other being smooth, but it will be understoodthat both can be grooved if preferred. In Figures 1 and 2 the roller I8is shown as having its grooves 23 extending peripherally but it is apossibility to resort to the construction shown in Figures 3 and 4wherein I have shown a roller 24, corresponding to the roller l8 buthaving its grooves 25 extending transversely instead ofcircumferentlally. It is within the purview of the invention tosubstitute the roller 24 for the roller l3. Regardless of which type ofroller is used it is another important feature of the invention that thetop surface of the basin bottom 4 is formed with a series of concentricgrooves 26 which will of course be filled by the sand charged into thebasin through the hopper opening 8. The theory is, and practice hasproved its correctness, that the sand or mixture filling the grooves 25will be packed by the rotating rollers to a rock-like hardness. Moreoverthe sand filling the grooves will project above them and thus definecircular ridges between which a thin layer of loose sand will beentrapped and maintained substantially stationary so as not to abradethe bottom 4 of the basin.

It will be observed that the shafts it are of unequal length so that thegrooved roller l8 will travel over the inner portion of the basin bottomwhile the roller l1 travels over the outer portion, the paths of the tworollers being staggered. It might also be mentioned, in passing, thatany desired means may be employed for effecting lubrication within therollers and that any desired means may be provided for excluding sandfrom hearing areas. However, these are mere mechanical details which donot enter into the essence of the invention and are consequently notillustrated.

The upper end of the shaft I0 is represented as reduced and threaded asat 28. Supported upon the shoulder formed by the enlarged portion l2 'ofthe shaft at the base of said reduced end is a sand pushing or sweepingelement 29, shown in detail in Figure 5. This device is formed with acentral hub portion 30 apertured to receive the reduced threaded end ofthe shaft l0 and recessed at its underside to fit snugly over the upperend of the shaft enlargement l2 with its flat sides i3. Arms 3| areprovided on the hub 30 and extend outwardly therefrom in oppositedirections. Se-

cured tothe arms 3| are outwardly extending arms 32 each formed withplurality of downwardly extending sweeping o. agitating members 33. Thehub 30 is secured to the upper end of the shaft ill by a nut 34 threadedonto the reduced extension 23 and the sweeper is so located that thearms 32 thereof are disposed at substantially right angles to the axesof the mulling rollers, The outermost sweeping members 33 of the arms 32are disposed in close proximity to the bottom and outer side wall 3 ofthe mulling basin. When the shaft I0 is rotated, the rollers will berevolved in a circular orbit but eccentric to the shaft and theoutermost sand sweeping members 33 will be turned with the rollers butin a concentric circular orbit outwardly of the roller orbit so thatsand within the basin will be worked toward the outside wall I. Thebottom of the basin is formed with a discharge opening 35 locatedoutwardly of the rollers and in the path of the outermost sweepers 33.The agitating members 33 located intermediate the lengths of the twoarms 32 are staggered, that is, the members upon the two different armsare located unequal distances from the shaft it. The agitating membersupon one arm will therefore move in concentric paths located between theconcentric paths of the members supported by the other arm. The membersare thus adapted to agitate the sand over substantially the entirebottom area of the basin after the rollers have passed over it.

Located at one side of the mulling basin in a position to receive thesand as it is discharged through the opening 35 is a cylindricalsand-diffusing drum 36. This drumis rotatably mounted between upstandingside wall members 31 supported by the base I and arranged adjacent theends of the drum. The drum is fixed to a shaft 33 which extendsoutwardly through the side walls 31 and is rotatably supported inbearings 39 mounted upon the outer sides of the walls 31. Thecylindrical outer surface of the drum is covered with wire bristles 43which form a brush surface.

An electric motor 4| is mounted upon the base I beneath the mullingbasin. Mounted upon the shaft of the motor is a sprocket wheel 42 whichis connected by a driving chain 43 with a sprocket wheel 44 fixed to thediffusing drum shaft 33. Another sprocket wheel 45 is also fixed to theshaft 38 and is connected by a drive chain 45 with a sprocket wheel 41fixed to a muller drive shaft 48 located beneath the muller basin. Theshaft 48 is supported by depending bearing brackets 49 mounted upon theunderside of the bottom 4 of the basin. Fixed to the shaft 43 is a smalldriving pinion III which meshes with the relatively large beveled gearll mounted upon the muller shaft Ill. The motor is thus adapted to driveboth the mulling rollers and the diffusing drum. .A belt pulley 5| isalso fixed to the drum shaft 39 and provides for the operation of theapparatus from a source of power other than the motor.

Mounted upon the base I of the apparatus is a centrifugal blower 52which is adapted to be driven by the shaft 38, through a belt and pulleyconnection 53, 54, and 55. A pipe leads from the blower 52 to adischarge nozzle 56 located directly beneath the discharge opening 35 ofthe mulling basin. This nozzle has a width substantially equal to thelength of the drum 35 and is directed outwardly through the brushportion the drum. The blower is continuously operated by the motor orother source of power along with the rest of the apparatus, and directsa continuous blast of air through the brush upon the drum. This airblast dries the sand and assists its discharge from the diffusing drum.

In the operation of the apparatus the sand is delivered into thefunnel-shaped hopper and passes through the opening 8 into the mullingbasin. This opening is located so that it will deliver sand to thecentral area only of the basin, inwardly of the rollers l1 and I8.Usually the sand has been used for previous molds, and much of it is ina lumpy condition. The muller may and often is used to mix fresh batchesof sand and clay, in which event the clay is added to the sand withinthe muller. The sand passing into the central portion of the basin isspread out by the rollers and worked along the bottom until it reachesthe outer edge, being thoroughly mulled or kneaded on the way by therollers, the loose sand A entrapped between the hard packed sand 13which fills and extends above the concentric grooves 26 in the basinbottom remaining substantially stationary so that the bottom will notbecome abraded, all as explained hereinbefore. The rollers may besupported in a slightly elevated position so as not to bear too heavilyupon the sand and interfere with its feed through the basin, forinstance by means similar to what is illustrated in my prior patent,.

though even if no such elevating means is provided, the rollers willnaturally swing, as the result of centrifugal force, upwardly from aposition resting on the bottom and will be spaced from the bottom asshown in Figure 2. The sand worked to the outer portion of the basin anddischarged through the opening 35 is delivered to the brush of thedifiusing drum 36 at one side of the shaft, carried upwardly by thedrum, subjected to the blast of'air from the nozzle 55, and cast outinto a hopper (not shown) at the opposite side of the shaft 38.

From the foregoing description and a study of the drawings it will beapparent that I have thus provided a simple and easily operated mullingdevice of rugged and durable construction which is adapted to operatecontinuously and efilciently for crushing or mulling and kneading sandmixtures and placing it in proper condition for use in making molds. Itis believed that the construction, operation and advantages should bereadily apparent to one skilled in the art without further explanation.

While I have shown and described the preferred embodiment of theinvention, it should be understood that the disclosure is merely anexemplification of the principles involved as the right is reserved tomake all such changes in the details of construction as will widen thefield of utility and increase the adaptability of the device providedsuch changes constitute no departure from the spirit of the invention orthe scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. A sand mulling machine comprising a stationary mulling basin having abottom and a side wall or rim, a shaft projecting upwardly through thebottom of said basin, a pair of axles pivotally mounted on said shaft, amulling roller mounted on each axle, said axles being of differentlengths, said bottom being formed with.

grooves concentric with said shaft, means for rotating said shaftwhereby said rollers are caused to travel over the bottom of said basin,whereby sand will be collected and packed within said grooves, said sandacting-to maintain a layer of unpacked sand immovable with respect tosaid packed sand during the operation of said rollers.

2. A sand mulling machine comprising a stationary mulling basin having abottom and a side wall or rim, means within the basin for dischargingthe sand, a hopper at the top of the basin adapted to discharge sandthereinto, a shaft projecting upwardly through the bottom of said basin,a pair of axles pivotally mounted on said shaft and on opposite sides ofthe center of said shaft, a mulling roller mounted on each axle,andmeans for rotating said shaft for causing said rollers to travel overthe bottom of said basin to efiect a sweeping action of the sandcontained therein, said bottom of said basin being formed withconcentric grooves within which sand may be packed by the action of therollers, said packed sand forming means to retain a layer of loose sandstationary with respect ,to said basin bottom during the travel of saidrollers.

WILLIAM H. NICHOLLS.

